Hydrodynamic Modeling for Flow and Velocity Estimation from an Arduino Ultrasonic Sensor

Round 1

Reviewer 1 Report

Comments for author File: Comments.pdf

Author Response

Dear reviewer, we sincerely appreciate your valuable corrections and suggestions for enhancing the article, and we are pleased with the outcomes. We trust that we have addressed all correction requests at the required level.

Reviewer 1 – (Comments and pdf review)

Reviewer 1 - Review of the Manuscript

"Hydrodynamic Modeling for Flow and Velocity Estimation from Arduino Ultrasonic Sensor" by Pereira et al.

Although I haven’t large experience in laboratory analysis, a careful reading of the manuscript has led me to form my own thoughts on the presented research.

Reviewer 1 - General comments

The Authors propose using a simple hydrodynamic model based on flood depth for estimating flow velocity along a channel. The model solves the one-dimensional Saint-Venant equations using the Preissmann implicit solution scheme. Model calibration relies on laboratory tests involving a facility made up of an experimental channel equipped with ultrasonic sensors and an Acoustic Doppler Velocimeter for flow velocity measurement. All the tests are performed under subcritical regime and variable bottom slopes and weir heights for four events (EVi). The authors replicated the experimental measures correctly after manually calibrating Manning’s coefficient for EV1, using objective functions and well-known and commonly used performance indicators. Validation was performed for the remaining three events, demonstrating the model's reliability for velocity estimation in transient flow conditions. The Authors found that calculated discharge and velocity showed a maximum variation of 40% for the same level compared to those estimated with the traditional rating curve method, stressing the need for more reliable velocity estimation methods in natural channels. The Authors finally remark on the practical implications of their findings.

Reviewer 1 - General impressions

The paper is well written and quite understandable. Narrative is flowing and the motivations of the work are clearly presented. Figures and Tables are well readable. I would just suggest to add the meaning of ADV when it firstly appear in the text for clarity. Maybe the Authors should minimize the reliability of a such simple model for natural rivers and emphasize that the Manning’s values may be very different and space-time varying over a natural channel.

Authors' Response: We sincerely appreciate the esteemed reviewer's comments, suggestions, and improvement requests. We want to highlight that we have incorporated the meaning of ADV in the caption of Figure 1 and the text (first occurrence), as suggested, in lines 98 and 99.

Authors' Response: Throughout the article, we have consistently emphasized the need for further studies to assess the application of the model in natural channels, as highlighted in the Abstract, line 13, DISCUSSION, line 420, and CONCLUSION, lines 442 and 463, sections. We acknowledge that laboratory experimentation has its limitations but is essential. We also recognize and agree that it is crucial to conduct extensive evaluations for natural channel conditions. Therefore, this topic will be addressed in our upcoming article, as the coefficient of Manning and other variables exhibit significant variability in natural channels. It is essential to note the limitations of each approach (laboratory/field conditions). We appreciate the valuable suggestions received and are currently in the process of developing another work specifically focused on natural channels. This upcoming publication will include model tests and alternative data acquisition methods conducted more frequently.

Reviewer 1 - Specific comments

I think the references about scientific validation of the results may be updated. See, for example, Gupta et al. (2009) and many subsequent works. For example, Kling-Gupta efficiency (KGE) is often preferred for scientific calibration in hydrology due to the capability to overcome the limitations of the most common NSE and RMSE.

Authors' Response: Regarding the efficiency of Kling-Gupta Efficiency (KGE), proposed by Gupta (2009) and modified by Kling (2012), despite being commonly used for hydrological calibration, it was not employed in this study. The focus of our study was on isolated events without periods of baseflow, and, in such cases, Nash-Sutcliffe Efficiency (NSE) and Root Mean Square Error (RMSE) are more commonly used and suitable performance indicators. However, we acknowledge that for continuous hydrological modeling, KGE could be a better and more appropriate option. A paragraph has been added to the CONCLUSIONS section, line 448, to justify the choice of the employed Objective Functions and the decision to exclude others.

Reviewer 1 - Specific comments

Discussion (Section 4) should be revised entirely. It is presented in a summary of the paper with considerations that are then proposed again in the conclusions. I suggest merging, summarize, and revising sections 4-5 and rewriting Discussion. I think the Authors should emphasize the novelty of their work if others have done no similar experiments or try to stress how their results align with other findings. Alternatively, they may split somehow the results section and leave some critical comments for discussion.

Authors' Response: The DISCUSSION section has been completely rewritten, but the decision was made to keep it separate from the CONCLUSIONS section solely for the purpose of organizing ideas.

Authors' Response: The novelty of our work was underscored by comparing it with similar studies, as requested, in the INTRODUCTION section, line 78, and further emphasized in the DISCUSSION, lines 368 and 389, section. Additionally, attention was drawn to technical terms within hydrology and hydraulics to ensure precision in conveying the study's findings.

Reviewer 1 - Specific comments

Finally just a typo in the bibliography: something upset in the first reference with a line number in the title.

-Aricò, C.; Nasello, C.; Tucciarelli, T. Using unsteady-state water level data to estimate channel 353 roughness and discharge hydrograph. Advances in Water Resources 2009, 32(8), 1223–1240. http://dx.doi.org/10.1016/j.advwatres.2009.05.001.

Authors' response: The reference has been corrected by removing the erroneously entered number 353, as outlined in the REFERENCES section, line 476.

Reviewer 1 - Specific comments

Line 305, add a comma after “6c”

Authors' Response: Commas were added after 6c to reference different figures.

Reviewer 1 - Specific comments

Overall, the work interests hydraulics and surface hydrology, and it deserves publication in the Journal “Hydrology”. However, major revisions are required of the authors to improve the discussion.

Authors' Response: The authors express their gratitude for the valuable contributions, which are crucial for enhancing the quality of the article. It is worth noting that the entire DISCUSSION section has been rewritten by the suggestions provided by the reviewers and other fellow assessors. This extensive revision was undertaken to better align the discussions with the substantive content of the article.

Reviewer 2 Report

This manuscript has a potential, however, it needs to be improved. The Authors should be able to show clearly the novelty of this study. Since the study focusses on the hydrodynamic modeling, it is important to indicate new contribution to the knowledge. To do so, the Authors should enrich state of the art in the aspect of related modeling. Methodology is recommended to be rewritten so that it is easier for the readers to understand how this study was conducted. Similarly, some figures and tables must be rearranged. Technical drawing of the channel including its observation stations and boundaries is necessary. Findings must be further explained especially for the high values of OFs, why it happened and will it be possible to lower. For example, the high errors indicated in velocity due to turbulence.

Comments for author File: Comments.pdf

Author Response

Dear reviewer, we sincerely appreciate your valuable corrections and suggestions for enhancing the article, and we are pleased with the outcomes. We trust that we have addressed all correction requests at the required level.

Reviewer 2 – Manuscript PDF

Parte superior do formulário

Reviewer 2 - Line 1:

Manuscrito Since the focus of this study is hydrodynamic modeling then the AU Sensor is better not to be written as it is. I suggest if I am allowed, I would like to propose.

The title becomes "The Development of Hydrodynamic Model in Estimating the Channel Discharge and Velocity.". The validation is conducted based on the lab experiment. The Authors must emphasize the novelty of this study, for example, is there anything new contribution in the modeling or any gap identified?

Authors' Response: The papper contribution lies in validating velocity and discharge data using a high-frequency velocimeter to assess the results obtained from hydrodynamic modelling employing solely water levels obtained with an ultrasonic sensor. The use of water levels with a hydrodynamic model for discharge estimation instead of the rating curve has been consistently investigated; however, few of these studies evaluate the variation in velocity during rapid flow changes, often relying on point data. This article employed a velocimeter with a frequency of 25 Hz, enabling the precise assessment of flow velocities under various conditions.

Authors' Response: In this way, we chose to retain the title of the article, as the ultrasonic sensor has proven to be a versatile and suitable tool for use as a low-cost water level gauge. Furthermore, the use of this gauge has been demonstrated to be feasible, as it allows for the acquisition of reliable water level results that can be used to estimate transient flow, which served as input data for the model or upstream boundary condition in the utilized modeling approach. In our upcoming study, we intend to further employ this sensor for data acquisition in natural channels, assessing its viability and applying the same methodology employed in this article. We have already obtained some results for natural channels, with plans to submit a new article on the subject next year, incorporating the suggestions provided by the reviewer.

Authors' Response: It is emphasized that the contribution/gap of the article has been included in the INTRODUCTION section, line 78.

Reviewer 2 - Line 68:

Authors are recommended to enrich state of the art of this study especially on the related hydrodynamic modeling and hysteresis phenomenon. Based on that, please indicate the knowledge gap and novelty of this study.

Authors' Response: Responded as per the previous item. However, in the INTRODUCTION section, studies on hydrodynamic modelling related to the hysteresis phenomenon were added, highlighting the difference and novelty of our study compared to existing ones. It emphasizes that this study's knowledge gap and novelty lie in the validation of velocity and discharge data using a high-frequency velocimeter to assess the results obtained from hydrodynamic modelling employing only water levels obtained with an ultrasonic sensor. Using water levels with a hydrodynamic model for discharge estimation, replacing the rating curve, has been consistently studied. Nevertheless, few works assess the velocity changes during rapid flow variations, often using point data.

Authors' Response: We also emphasize the need to highlight the "gap" and novelty of the study in the DISCUSSION section, line 38.

Reviewer 2 - Line 86:

Authors are recommended to rewrite the research methodology so that it clears for the readers how this experiment and hydrodynamics modeling were conducted. Calibration and validation are very important to be clearly defined. Any assumptions or limitations must be well informed here.

Authors' Response:  We made several modifications to the methodology, as requested by the 3 reviewers, to make it more straightforward.

Reviewer 2 - Line 88:

Authors are recommended to provide a drawing of the channel longitudinal profile with all sensor stations, ADV point, stilling basin, etc.

Authors' Response: In the MATERIALS AND METHODS section, line 96, Figure 1d has been added to depict the longitudinal profile design of the artificial channel, illustrating the locations of all sensors and utilized Acoustic Doppler Velocimeters (ADV).

Authors' Response: It was further clarified in line 159, that the H5 sensor was installed in a section where the backwater effect caused by the spillway is minimized. This is because the downstream reservoir is located at a lower elevation, approximately 1.50 m, and thus does not interfere with the flow within the artificial channel. Figure 1a, line 96 can also verify the reservoir's location.

Reviewer 2 - Line 89: ADV

Authors' Response: It is noteworthy that the meaning of ADV has been added to the caption of Figure 1, as requested.

Reviewer 2 - Line 99:

Authors are recommended to provide information on the H1-H5 so that readers can easily understand how this experiment was conducted.

The channel longitudinal profile may help to describe the experiment. Then, as weir is installed downstream, how do the Authors examine the influence of backwater on the velocities?

The Authors are recommended to rearrange the manuscript i.e. figures and tables, so that the readers can easily understand the content.

Authors' Response: Information from H1 to H5 has been added to the text, line 113, to allow readers to comprehend how the experiment was conducted easily.

Authors' Response: The longitudinal profile of the artificial channel has been incorporated to enhance the description of the experiment, as shown in Figure 1d. Additionally, it has been specified in line 150 that sensor H5 was installed in a section less affected by the backwater effect caused by the spillway, given that the reservoir is located downstream. The sensor is positioned at a lower elevation, approximately 1.50 m, thereby avoiding any interference with the flow within the artificial channel.

Authors' Response: In addition to providing the requested information as suggested by the reviewer, we acknowledge the valuable recommendations to enhance the clarity and focus of the manuscript. Consequently, Figures 1 and 2 have been reorganized to facilitate a more straightforward comprehension of the study for readers.

Reviewer 2 - Line 142:

Q = Cd B H^(3/2), does the value of 0.461 represents the component of Cd and B? How does the value of 0.461 is estimated? Is there any rating curve developed from the experiment?

Authors' Response: Exactly. The equation for this type of spillway was calibrated according to Oliveira et al. (2016), where the authors Pereira and Formiga are co-authors, It was mentioned in the text, line 154.

- OLIVEIRA, F. A.; PEREIRA, T. S. R.; SOARES, A. K.; FORMIGA, K. T. M. Uso de modelo hidrodinâmico para determinação da vazão a partir de medições de nível. Revista Brasileira de Recursos Hídricos – RBRH, v. 21, n. 4, p.707-718, 2016. http://dx.doi.org/10.1590/2318-0331.011616007

Reviewer 2 - Line 145:

Which point of water level measurement represents the H in the formula?

Authors' Response: The water level measurement point representing H in the formula is H5, as added in the variable description of Equation 4, line 159.

Reviewer 2 - Line 214:

Further explanation of the highlighted error values is needed. It seems that the stilling basin failed to stabilize the flow.

Authors' Response: We attempted to explain the process in the discussion. The turbulence of the attenuation reservoir could not fully stabilize; this is an input data, as measured at the first point (H1).

Reviewer 2 - Line 270:

Authors' response: Figure 4, EV1, has been corrected by replacing Point 2 and Point 4 with Section 2 and Section 4, respectively.

Reviewer 2 - Line 296:

These segments are not clear, thus the channel longitudinal profile is important.

Authors' Response: The channel's longitudinal profile has been added per the previous items. The mentioned segments represent Peaks 1, 2, 3, and 5 of the EV1, which were separated to visually facilitate the hysteresis phenomenon against the loop and traditional rating curves. This separation was necessary as the information in the previously generated figure overlapped, making it challenging to discern which data corresponded to each peak at line 299.

Reviewer 2 - Line 372:

These sentences are best explained in the results part so that readers can understand the relevancy.

Authors' Response: We agree. The CONCLUSIONS section, including this sentence, has been restructured as requested.

Reviewer 2 - Line 373: The objective functions (OFs)

Authors' Response: The acronym has been replaced with "The objective functions (OFs)," as requested, line 445.

Reviewer 2 – Modified Field Code

- Brusa, L.C.; Clarke, R.T. Erros envolvidos na estimativa da vazão máxima utilizando curva-chave.  Estudo de caso: bacia do rio Ibicuí, RS.  Revista Brasileira de Recursos Hídricos 1999, 4(3), 91-95. http://dx.doi.org/10.21168/rbrh.v4n3.p91-95

Authors' Response: We have reviewed the code; however, it appears as documented on the journal's website, as evidenced by the screenshot of the page and the provided link.

https://www.abrhidro.org.br/SGCv3/publicacao.php?PUB=1&ID=48&SUMARIO=671&ST=erros_envolvidos_na_estimativa_da_vazao_maxima_utilizando_curva_chave_caso_de_estudo_bacia_do_rio_ibicui_rs

Reviewer 2 - Comment on the Website

This manuscript has potential, but needs to be improved. The authors should be able to clearly show the novelty of this study. As the study focuses on hydrodynamic modeling, it is important to indicate new contributions to knowledge. To this end, the Authors must enrich the state of the art in the modeling aspect. related contribution. It is recommended that the methodology be rewritten so that it is easier for readers to understand how this study was ongoing. Likewise, some figures and tables must be reorganized. A technical drawing of the channel, including its observation stations and limits, is required. The results should be explained in more detail, especially for the high values of OFs, as this happened and it will be possible to reduce them. For example, the high errors indicated in speed due to turbulence.

Author's Response: Each inquiry has been individually addressed in the preceding sections, where the reviewer has requested specific corrections to be made separately.

Reviewer 3 Report

The present paper “ Hydrodynamic Modeling for Flow and Velocity Estimation  from Arduino Ultrasonic Sensor” deals with the proposal of a methodology for measuring Flow in hydraulic modelling

This is a very interesting paper, but some comments are proposed by this reviewer.

·        Abstract should point out the novelty of the paper

·        Introduction is well presented, but some detail about the objectives of the research would  be welcome. Furthermore the comparison with previous models and the main contributions of the present research would be also welcome in this section.

·        Matherials and methods are very well developped. The accuracy of the proposal, the calibration and the sensiticity analysys proposed in adequate and well described in the document. There is a very important experimental and numerical research and it is well described in the document.

·        Discussion is well described

·        Conclusions are well presented but it would be interesting to see some indications about the novelty of the research and the degree of achievement of the objectives would be indicated in this final part of the document

Author Response

Dear reviewer, we sincerely appreciate your valuable corrections and suggestions for enhancing the article, and we are pleased with the outcomes. We trust that we have addressed all correction requests at the required level.

Authors' Response: Reviewer 3 (comments on the website)

Reviewer 3  - This is a very interesting article, but some comments are proposed by this reviewer.

Authors' Response: We sincerely appreciate the requested considerations and will endeavor to address each of them to enhance the article's quality.

Reviewer 3  - The summary must highlight the novelty of the article.

Authors' Response: The paper's novelty was added and reinforced in the abstract and further clarified in the INTRODUCTION section, line 460, as other reviewers had also mentioned and requested this action. Thus, the description of our study on hydrodynamic modelling related to the hysteresis phenomenon was strengthened, emphasizing the difference in our study compared to others. This study's knowledge gap and innovation lie in the validation of velocity and discharge data using a high-frequency velocimeter to assess the results obtained from hydrodynamic modeling employing only water levels obtained with an ultrasonic sensor. The use of water level with a hydrodynamic model for discharge estimation instead of the rating curve has been consistently studied; however, few of these works assess the velocity changes during rapid flow transitions, often employing point data. This article employed a velocimeter with a frequency of 25 Hz, enabling the precise evaluation of flow velocities under various conditions.

Authors' Response: The "gap" and novelty of the study were also emphasized in the DISCUSSION section, line 389, as mentioned earlier.

Reviewer 3  - The introduction is well presented, but details about the research objectives would be welcome. Furthermore, this section would also welcome comparison with previous models and the main contributions of the present research.

Authors' Response: The research objective was outlined in the INTRODUCTION section, line 71, as requested. Additionally, the study's contribution in comparison to other authors' works was highlighted, line 78.

Reviewer 3  - The materials and methods are very well developed. The proposal's accuracy, calibration, and sensitivity analysis are adequate and well described in the document. There is very important experimental and numerical research that is well described in the document. The discussion is well described. The conclusions are well presented, but it would be interesting to see some indications about the novelty of the research and the degree of achievement of the objectives would be indicated in this final part of the document.

Authors' Response: We are very grateful for the reviewer's feedback regarding the materials and methods, as well as the discussions.

Authors' Response: Regarding the indication of research novelties in the CONCLUSION section, based on the proposed objective, it is observed that we have successfully addressed it. We have also made adjustments in the CONCLUSIONS section, incorporating the corrections suggested by the reviewer and other revisions. We believe that we have satisfactorily addressed the request by presenting the primary contribution of the research to the understanding and enrichment of the study area.

Round 2

Reviewer 1 Report

The Authors significantly improved the quality of their manuscript by providing a more coherent discussion of the results and by addressing all the comments received. The Authors have also revised individual sentences in the abstract and within the manuscript by occasionally adding keywords to aid the narrative. 

I agree with publication in the present form in the journal "Hydrology".

Reviewer 2 Report

The Authors have added the necessary points and revised what was asked to complete. One typo, however, is found in the Figure 1. Finally, I do hope this research can be a good contribution in hydraulic studies.

Comments for author File: Comments.pdf